Are you an American or Western European man exchanging emails with a girl from Russia? I was contacted by a girl who turned out to be a scammer. Reader Derrick put together some great advice how to detect scammers.
I only have one advice (#8) to add: If a Russian girl tells you that she will get a visa to the USA instead of inviting you, that is - under the current immigration law - a SURE sign that SHE LIES.

Here is the process how a Russian woman can come to the USA:

If she is considered a relatively young/ attractive woman (let's say under 40, hope I don't hurt anyone's feelings here), then there is virtually NO CHANCE THAT SHE GETS A TOURIST VISA TO THE USA. First the Russian Federation will not allow her to leave the country. Then, even if she was getting out, the USA will deny her admission. The reasoning is that she is considered a risk. How could she not be a risk? If she had family in Russia (husband, children) or a valuable business or real estate. Most likely the woman who writes you will be considered a risk. The only way for her to get a visa into the USA is this procedure:

1. GOOGLE or websearch the first part of the scammers first emails and/or 'profile'. SEE HOW MANY OTHER SITES their listed on! RECORD THOSE SITES FOR FUTURE REFERENCE. THAT alone can give you a good idea IF your dealing with a scammer OR not.
   
2. GOOGLE or websearch the return email address. See how many 'hits' come from that search and also note all the sites. (many times you'll see the email end up on a 'scammers list') IF YOU FIND THE EMAIL ADDRESS LISTED ON A SCAMMER LIST - don't bother further, your only fooling yourself - no matter what excuse they might give you.
   
3. FROM THE START - ASK FOR SPECIFIC INFOMATION! A full name, address, phone number - something. OFFER THE SAME in exchange, except make it a P.O. box and a CELL PHONE rental card that will protect your identity. If you see your requests ignored, which you usually will, don't waste your time further.
   
4. ALWAYS ASK SPECIFIC QUESTIONS that would REQUIRE A SPECIFIC ANSWER outside the use of FORM LETTERS. IF YOU FIND your questions go unaddress in your reply emails from 'them/her' - YOUR DEALING WITH A SCAMMER. Again, don't bother further.
   
5. DON'T WAIT 6 MONTHS to offer to talk with the PROSPECT by phone! WHAT A TOTAL WASTE OF TIME! IF THERE IS CHEMISTRY OR APPEARS 'INTEREST' BETWEEN THE TWO OF YOU - then sieze the opportunity. ARRANGE A PHONE CALL! International rates to Russia and most places are reasonably cheap. IF YOU GET THE REPLY ' I'M SO POOR I DON'T HAVE ACCESS TO A PHONE' - drop the whole thing, your only wasting your time and WILL BE SCAMMED at some point in the future.
   
6. PHOTO FLOOD! IF IT/SHE/HIM/THEM - LOOK TOO GOOD TO BE TRUE - THEN IT PROBABLY IS! MOST IF NOT ALL OF THE SCAMMES USE PHOTOS OF MODELS IN THEIR HOME COUNTRIES TO POSE ON THE NET IN THEIR PROFILE(s)! Consider this - IF THEY LOOK like a MODEL then tell you they're so poor they don't have access to a phone - YOUR BEING SCAMMED!
   
   ASK FOR A SPECIAL PHOTO TO BE TAKEN. IF YOU SENT YOURS, HAVE THEM TAKE A PHOTO SHOWING THEM HOLDING UP YOUR PHOTO IN THE PICTURE! That is a good 'scammer filter' - even the most adept with Photoshop will easily be spoted.
   
   BETTER STILL - ASK THEM TO TAKE A PHOTO THAT SHOWS THEM HOLDING A CURRENT NEWPAPER OF YOUR CHOICE OR THEIR COUNTRY, WITH A RESOLUTION THAT YOU CAN READ THE DATE! NOT some low grade - grainy photo! FEW WILL EVER DO THAT.
   
   AT THE LEAST - ASK THEM FOR A PHOTO of them wearing a specific combination of clothes and/or colors - something different then the usual 'model clothing' - most use to send out. OR AN OBJECT - TOASTER, ELECTRIC CLOCK, BY A COUCH, IN A ROCKING CHAIR something that would be very hard to use PHOTOSHOP to just PUT in another FILE PHOTO.
   
   *** IF this person is real or sincere, they won't mind doing this for you! ALSO - offer to do the same for their comfort also - that is only fair.
   
7. IF THINGS GET SERIOUS - then ASK THEM TO DELETE ALL THEIR OTHER WEB PROFILE POSTS! CHECK ON THE ONES YOU NOTED EARLIER! Again, IF THEIR SINCERE - they will - happily as your their DREAM and future!
   
8. If she talks about getting a visa or that she needs money to get a travel visa to the USA, she lies. See the proper course of action described at the top.

From http://www.delphifaq.com/faq/russian_marriage_scams/f991.shtml